Diversity of O-linked glycosylation patterns between species - Characterization of 25 carbohydrate chains from oviducal mucins of Rana ridibunda

Amphibia egg jelly coats are formed by components secreted along the oviduc t. These secretion products overlay the oocytes as they pass along the diff erent oviducal portions. Mucin type glycoproteins are the major constituent s of the egg jelly coats. In this study, the O-linked carbohydrate chains: of the jelly coats surrounding the eggs of Rana ridibunda were released by alkaline borohydride treatment. Fractionation of the mixture of O-linked ol igosaccharide-alditols was achieved by a combination of chromatographic tec hniques including gel-permeation chromatography, ion-exchange chromatograph y and high-performance liquid chromatography using an amino-bonded silica c olumn. The primary structures of these O-glycans were determined by one-dim ensional and two-dimensional H-1-NMR spectroscopy and matrix-assisted laser -desorption-ionization-time-of flight mass spectrometry. 25 oligosaccharide structures, possessing a core consisting of Gal(beta1-3)GalNAc-ol with or without branching through a GlcNAc residue linked (beta1-6) to the GalNAc r esidue (core type 2 or core type 1, respectively) are described. The most r epresentative antennae are: HSO3(6)[Fuc(alpha1-3)]GlcNAc; Gal(beta1-2)Gal; Gal(beta1-2)Gal(alpha1-3)[Fuc(alpha1-2)]Gal; GlcA(beta1-3)-Gal(beta1-3)[Fuc (alpha1-2)]Gal; GalNAc(alpha1-4)Gal(beta1-4)Gal; Gal(beta1-3)GalNAc(alpha1- 4)Gal(beta1-4)Gal and GlcA(betaI-3)Gal(beta1-3)GalNAc. These results confir m the species-specific O-glycosylation of Amphibia oviducal mucins. The sig nificance of this observation should be linked to a symbiotic role of carbo hydrates involved in host-parasite interactions.